expat and leading white spaces

I was looking around to see if there might be a way to allow
expat/libwww to accept xml files with leading white spaces before the
standard <?xml version="1.0" ?> line without invoking the
XML_ERROR_MISPLACED_XML_PI.
 
I know that it is invalid to do so but this is one of those quirky
requests to make the parser less forgiving for this case.
 
Any help appreciated
Thanks
 
raj